Manufacturing method of display apparatus utilizing dam portion and display apparatus manufactured using the method

ABSTRACT

A manufacturing method of a display apparatus, in which a defect rate in a manufacturing process is reduced and product reliability is increased, and a display apparatus manufactured according to the method are provided. The manufacturing method includes: forming a first pixel electrode on a substrate; forming an insulating layer; forming a first dam portion; forming a first lift-off layer; forming a first mask layer; forming a first intermediate layer; forming a first opposite electrode; forming a first insulating protective layer; and removing the first dam portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/437,792, filed Jun. 11, 2019, which claims priority to and thebenefit of Korean Patent Application No. 10-2018-0093138, filed Aug. 9,2018, the entire content of both of which is incorporated herein byreference.

BACKGROUND 1. Field

One or more embodiments relate to a display apparatus and amanufacturing method of the display apparatus, and more particularly, toa manufacturing method of a display apparatus in which a defect rate inthe manufacturing process is reduced and product reliability isincreased, a display apparatus manufactured using the method, and adisplay apparatus amenable to being manufactured according to a methodyielding a reduced defect rate and increased product reliability.

2. Description of the Related Art

Among display apparatuses, organic light-emitting display apparatuseshave wide viewing angles, high contrast, and fast response speeds, andthus are drawing attention as a next-generation display apparatus.

An organic light-emitting display apparatus typically includes a thinfilm transistor and organic light-emitting elements on a substrate, andthe organic light-emitting elements emit light themselves. An organiclight-emitting element may include a pixel electrode, an oppositeelectrode facing the pixel electrode, and an emissive layer between thepixel electrode and the opposite electrode. Organic light-emittingdisplay apparatuses are used as display units of compact products suchas mobile phones or as display units of large-size products such astelevisions.

For an organic light-emitting display apparatus implementing full color,light of different colors is emitted from different pixel areas, and anemissive layer of each pixel and an opposite electrode integrally formedin a plurality of pixels may be formed using a deposition mask. As theresolution of organic light-emitting display apparatuses graduallyincreases, the width of an open slit of a mask used during a depositionprocess gradually decreases and there is a demand for dispersion thereofto be gradually reduced. Furthermore, to manufacture a high-resolutionorganic light-emitting display apparatus, there is a demand to reduce orremove a shadow effect. Accordingly, a deposition process may beperformed in which a substrate and a mask are in close contact with eachother.

SUMMARY

One or more embodiments include a manufacturing method of an organiclight-emitting display apparatus, whereby a defect rate during amanufacturing process is reduced and product reliability is enhanced,and the organic light-emitting display apparatus manufactured by usingthe manufacturing method. However, the above objective is an example,and the scope of the present disclosure is not limited by saidobjective.

Additional aspects may be set forth in part in the description whichfollows and, in part, may be apparent from the description.

According to one or more embodiments, a method of manufacturing adisplay apparatus, includes: forming a first pixel electrode foremission of a first color, a second pixel electrode for emission of asecond color, and a third pixel electrode for emission of a third coloron a substrate; forming an insulating layer, the insulating layercovering edges of the first pixel electrode and having a first openingexposing a center portion of the first pixel electrode, the insulatinglayer covering edges of the second pixel electrode and having a secondopening exposing a center portion of the second pixel electrode, theinsulating layer covering edges of the third pixel electrode and havinga third opening exposing a center portion of the third pixel electrode;forming a first dam portion on the insulating layer around the firstopening; forming a first lift-off layer on the insulating layer aroundthe outside of the first dam portion such that the first lift-off layercovers the second pixel electrode and the third pixel electrode andcomprises an opening exposing the first pixel electrode; forming a firstmask layer on the first lift-off layer, the first mask layer having afirst open portion corresponding to the first opening; forming a firstintermediate layer on the first pixel electrode through the first openportion; forming a first opposite electrode on the first intermediatelayer through the first open portion; forming a first insulatingprotective layer on the first opposite electrode through the first openportion; and removing the first mask layer, the first lift-off layer,and the first dam portion.

The first dam portion and the first mask layer may include a samematerial.

The removing of the first mask layer, the first lift-off layer, and thefirst dam portion may include simultaneously removing the first masklayer, the first lift-off layer, and the first dam portion by using afirst solution.

A height of the first dam portion may be equal to a height of the firstlift-off layer.

An edge of the first mask layer around the first open portion may havean undercut shape protruding beyond the first dam portion toward thefirst opening.

An upper surface of the first dam portion may contact a lower surface ofthe first mask layer such that the first dam portion supports the firstmask layer from below.

The first dam portion and the first lift-off layer may be spaced apartfrom each other.

The method may further include, before forming the first dam portion,patterning an auxiliary electrode on the insulating layer.

The first opposite electrode may directly contact the auxiliaryelectrode to electrically connect to the auxiliary electrode.

The first insulating protective layer may be formed of an inorganicinsulating material.

An end of the first insulating protective layer may be spaced apart fromthe first dam portion.

A height of the first dam portion may be less than a height of the firstlift-off layer.

The first dam portion and the first mask layer may contact each other.

The first lift-off layer may include a fluorous solvent base resin.

The first dam portion may have a closed loop shape surrounding the firstopening.

The method may further include, after removing the first mask layer, thefirst lift-off layer, and the first dam portion: forming a second damportion on the insulating layer around the second opening; forming asecond lift-off layer on the insulating layer around the outside of thesecond dam portion such that the second lift-off layer covers the firstpixel electrode and the third pixel electrode and comprises an openingexposing the second pixel electrode; forming a second mask layer on thesecond lift-off layer, the second mask layer having a second openportion corresponding to the second opening; forming a secondintermediate layer on the second pixel electrode through the second openportion; forming a second opposite electrode on the second intermediatelayer through the second open portion; forming a second insulatingprotective layer on the second opposite electrode through the secondopen portion; and simultaneously removing the second mask layer, thesecond lift-off layer, and the second dam portion by using an identicaletching solution.

The second dam portion and the second mask layer may include a samematerial.

The method may further include, after removing the second mask layer,the second lift-off layer, and the second dam portion: forming a thirddam portion on the insulating layer around the third opening; forming athird lift-off layer on the insulating layer around the outside of thethird dam portion such that the third lift-off layer covers the firstpixel electrode and the second pixel electrode and comprises an openingexposing the third pixel electrode; forming a third mask layer on thethird lift-off layer, the third mask layer having a third open portioncorresponding to the third opening; forming a third intermediate layeron the third pixel electrode through the third open portion; forming athird opposite electrode on the third intermediate layer through thethird open portion; forming a third insulating protective layer on thethird opposite electrode through the third open portion; andsimultaneously removing the third mask layer, the third lift-off layer,and the third dam portion by using an identical etching solution.

The third dam portion and the third mask layer may include a samematerial.

A display apparatus manufactured using the method described above isprovided.

In addition to the aforesaid details, other aspects, features, andadvantages will be clarified from the following drawings, claims, anddetailed description.

These general and specific embodiments may be implemented by using asystem, a method, a computer program, or a combination of the system,the method, and the computer program.

These and/or other aspects will become apparent and more readilyappreciated from the following description of embodiments of the presentdisclosure, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a display apparatus according to an embodimentof the present disclosure;

FIG. 2 is an equivalent circuit diagram of a pixel of a displayapparatus according to an embodiment of the present disclosure;

FIG. 3 is a cross-sectional view of a step of a manufacturing operationof a display apparatus according to an embodiment of the presentdisclosure;

FIGS. 4A through 4D are cross-sectional views and a plan view of a stepof a manufacturing process of a display apparatus according to anembodiment of the present disclosure;

FIGS. 5A through 5D are cross-sectional views and a plan view of a stepof a manufacturing process of a display apparatus according to anembodiment of the present disclosure;

FIGS. 6A through 6D are cross-sectional views and a plan view of a stepof a manufacturing process of a display apparatus according to anembodiment of the present disclosure;

FIG. 7 is a cross-sectional view of a display apparatus according to anembodiment of the present disclosure;

FIG. 8 is a cross-sectional view of a step of a manufacturing operationof a display apparatus according to another embodiment of the presentdisclosure;

FIG. 9 is a cross-sectional view of a step of a manufacturing operationof a display apparatus according to another embodiment of the presentdisclosure; and

FIG. 10 is an enlarged view of a region B of FIG. 9.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. The present disclosure and the inventive aspects thereof can,however, be embodied in different forms. The present disclosure shouldtherefore not be construed as being limited to the descriptions setforth herein. Rather, these embodiments are provided as examples so thatthis disclosure will be thorough and complete, and will fully convey theaspects and features of the present invention to those skilled in theart. Accordingly, processes, elements, and techniques that are notnecessary to those having ordinary skill in the art for a completeunderstanding of the aspects and features of the present invention maynot be described. Unless otherwise noted, like reference numerals denotelike elements throughout the attached drawings and the writtendescription, and thus, descriptions thereof will not be repeated. In thedrawings, the relative sizes of elements, layers, and regions may beexaggerated for clarity. As used herein, the term “and/or” includes anyand all combinations of one or more of the associated listed items.Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

Since the present disclosure may have various modifications and severalembodiments, embodiments are shown in the drawings and will be describedin detail. Effects, features, and a method of achieving the same will bespecified with reference to the embodiments described below in detailtogether with the attached drawings. However, the embodiments may havedifferent forms and should not be construed as being limited to thedescriptions set forth herein.

While such terms as “first,” “second,” etc., may be used to describevarious components, elements, regions, layers and/or sections, suchcomponents must not be limited to the above terms. The above terms areused only to distinguish one component from another. Thus, a firstelement, component, region, layer or section described below could betermed a second element, component, region, layer or section, withoutdeparting from the spirit and scope of the present invention.

An expression used in the singular encompasses the expression of theplural, unless it has a clearly different meaning in the context.

In the embodiments below, it will be further understood that the terms“comprise” and/or “have” used herein specify the presence of statedfeatures or components, but do not preclude the presence or addition ofone or more other features or components.

In the embodiments below, it will be understood when a portion such as alayer, an area, or an element is referred to as being “on” or “above”another portion, it can be directly on or above the other portion, orintervening portion may also be present.

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,”“above,” “upper,” and the like, may be used herein for ease ofexplanation to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or in operation, in additionto the orientation depicted in the figures. For example, if the devicein the figures is turned over, elements described as “below” or“beneath” or “under” other elements or features would then be oriented“above” the other elements or features. Thus, the example terms “below”and “under” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (e.g., rotated 90 degrees or at otherorientations) and the spatially relative descriptors used herein shouldbe interpreted accordingly.

Sizes of components in the drawings may be exaggerated or contracted forconvenience of explanation. For example, since sizes and thicknesses ofcomponents in the drawings are arbitrarily illustrated for convenienceof explanation, the following embodiments are not limited thereto.

When a certain embodiment may be implemented differently, a specificprocess order may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order.

In the embodiments below, when a layer, an area, or an element is“connected”, it may be construed that the layer, area, or element isconnected not only directly but also through other constituent elementsinterposed therebetween. For example, when a layer, an area, or anelement is “electrically connected”, it may be in direct contact or maybe in contact through other constituent elements interposedtherebetween.

As discussed above, deposition processes may be performed with asubstrate and a mask in close contact with each other, for example tomanufacture a high-resolution OLED apparatus or to reduce or remove ashadow effect. When a deposition process is performed with a substrateand a mask are in close contact with each other, the mask may damagelayers on a pixel electrode.

FIG. 1 is a plan view of a display apparatus (or a substrate of adisplay apparatus) according to an embodiment of the present disclosure.

The display apparatus includes a display area DA where an image may bedisplayed and a peripheral area PA outside the display area DA, asillustrated in FIG. 1. FIG. 1 may be understood as illustrating asubstrate 100 included in the display apparatus. For example, it may beunderstood that the substrate 100 includes the display area DA and theperipheral area PA.

In the display area DA, pixels emitting different colors from each otherare arranged. For example, FIG. 1 illustrates first through third pixelsPX1, PX2, and PX3 emitting red, green, and blue light, respectively.While FIG. 1 illustrates the first through third pixels PX1, PX2, andPX3 in a staggered arrangement (e.g., a PenTile arrangement used in someSamsung Display Co., Ltd. products), the arrangement of pixels may bemodified in various manners without departing from the scope of thepresent disclosure, and the present disclosure is not limited to anyparticular arrangement.

The peripheral area PA may be a non-display area in which a driver, apower voltage supply line, or the like used to provide pixels with anelectrical signal or power may be arranged. The peripheral area PA mayinclude a pad which is an area to which an electronic device or aprinted circuit board or the like may be electrically connected.

FIG. 2 is an equivalent circuit diagram of a pixel of a displayapparatus according to an embodiment of the present disclosure.

Referring to FIG. 2, the pixel includes a pixel circuit PC and a displaydevice connected to the pixel circuit PC. An organic light-emittingdiode OLED is illustrated as a display device in FIG. 2. The pixelcircuit PC may include a first thin film transistor T1, a second thinfilm transistor T2, and a storage capacitor Cst.

The second thin film transistor T2 is a switching thin film transistor,is connected to a scan line SL and a data line DL, and transfers, to thefirst thin film transistor T1, a data voltage input via the data line DLaccording to a switching voltage input via the scan line SL. The storagecapacitor Cst is connected to the second thin film transistor T2 and adriving voltage line PL and stores a voltage corresponding to thedifference between a voltage received from the second thin filmtransistor T2 and a first power voltage ELVDD supplied to the drivingvoltage line PL.

The first thin film transistor T1 is a driving thin film transistor, isconnected to the driving voltage line PL and the storage capacitor Cst,and may control a driving current Id flowing through the organiclight-emitting diode OLED from the driving voltage line PL in accordancewith a voltage value stored in the storage capacitor Cst. The organiclight-emitting diode OLED may emit light having a brightness via adriving current Id. An opposite electrode (for example, a cathode) ofthe organic light-emitting diode OLED may receive a second power voltageELVSS.

With reference to FIG. 2, it is described that the pixel circuit PCincludes two thin film transistors and one storage capacitor, but thepresent disclosure is not limited thereto. The number of thin filmtransistors and the number of storage capacitors may be varied accordingto a design of the pixel circuit PC without departing from the scope ofthe present disclosure.

FIG. 3 is a cross-sectional view illustrating a part of a manufacturingprocess of a display apparatus according to an embodiment, taken alongline A-A′ of FIG. 1.

Referring to FIG. 3, a pixel circuit PC used to drive each of the firstthrough third pixels PX1, PX2, and PX3 is formed on the display area DAof the substrate 100. Although not illustrated in the drawing, a bufferlayer (not shown) may be first formed on the substrate 100 beforeforming the pixel circuit PC. The pixel circuit PC may include the thinfilm transistors and the storage capacitor or the like described withreference to FIG. 2.

The substrate 100 may include a polymer resin such as polyethersulphone(PES), polyacrylate (PAR), polyetherimide (PEI), polyethylenenaphthalate (PEN), polyethylene terephthalate (PET), polyphenylenesulfide (PPS), polyarylate, polyimide (PI), polycarbonate (PC),cellulose acetate propionate (CAP), or the like.

A first insulating layer 110 is formed on the pixel circuit PC. Thefirst insulating layer 110 may cover the pixel circuit PC and may be aplanarization insulating layer providing a relatively planar surface.The first insulating layer 110 may include, for example, an organicinsulating material such as PI.

Elements of the pixel circuit PC, for example a semiconductor layer of athin film transistor, a gate electrode, a source electrode, a drainelectrode, electrode plates of a storage capacitor, or the like may beformed between the substrate 100 and the first insulating layer 110. Inaddition, one or more inorganic and/or organic insulating layers thatmay be formed between a semiconductor layer of a thin film transistorand a gate electrode, between the gate electrode and a source or drainelectrode, and between electrode plates of a storage capacitor may befurther formed between the substrate 100 and the first insulating layer110.

The first through third pixels PX1, PX2, and PX3 may include a firstorganic light-emitting diode OLED1 (see FIG. 7), a second organiclight-emitting diode OLED2 (see FIG. 7), and a third organiclight-emitting diode OLED3 (see FIG. 7), respectively, which areconnected to pixel circuits PC.

First, as illustrated in FIG. 3, first through third pixel electrodes211, 212, and 213 that are electrically connected to respective pixelcircuits PC are formed on the first insulating layer 110. The firstpixel electrode 211 may be for emission of the first color, the secondpixel electrode 212 may be for emission of the second color, and thethird pixel electrode 213 may be for emission of the third color. Thefirst color, the second color, and the third color may be selected froma red color, a green color, a blue color, a white color, or acombination of thereof.

The first through third pixel electrodes 211, 212, and 213 are formed onthe first insulating layer 110 by patterning them such that they areapart from each other. The first through third pixel electrodes 211,212, and 213 may include a reflective layer including silver (Ag),magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au),nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), and/or acompound thereof.

In some embodiments, the first through third pixel electrodes 211, 212,and 213 may include the above-described reflective layer and atransparent conductive oxide (TCO) layer on and/or under theabove-described reflective layer. The TCO layer may include, forexample, an indium tin oxide (ITO), an indium zinc oxide (IZO), a zincoxide (ZnO), an indium oxide (In₂O₃), an indium gallium oxide (IGO), oran aluminum zinc oxide (AZO). For example, the first through third pixelelectrodes 211, 212, and 213 may be a triple layer of ITO/Ag/ITO.

A second insulating layer 120 defining an emission area of each of thefirst through third pixel electrodes 211, 212, and 213 is formed on thefirst through third pixel electrodes 211, 212, and 213. Ends (e.g.,edges) of the first through third pixel electrodes 211, 212, and 213 arecovered by the second insulating layer 120, and openings respectivelycorresponding to pixels, for example, first through third openings OP11,OP21, and OP31 exposing center portions of the first through third pixelelectrodes 211, 212, and 213, respectively, are formed in the secondinsulating layer 120 to thereby define pixels.

The second insulating layer 120 may be formed of, for example, anacrylic organic material or an organic insulating material such asbenzocyclobutene (BCB). According to another embodiment, the secondinsulating layer 120 may be formed of an inorganic insulating materialsuch as a silicon nitride (SiNx), a silicon oxide (SiOx), a siliconoxynitride (SiON), or a silicon oxycarbide (SiOC). When forming thesecond insulating layer 120 by using an inorganic insulating material, apath through which oxygen or moisture may penetrate may be blocked,thereby preventing or minimizing damage to an organic light-emittingdiode due to oxygen or moisture.

An auxiliary electrode 130 is formed on the second insulating layer 120.The auxiliary electrode 130 may be formed on the second insulating layer120 exclusively. The auxiliary electrode 130 may be formed directly onan upper surface of the second insulating layer 120 and be in directcontact with the upper surface of the second insulating layer 120. Insome embodiments, the auxiliary electrode 130 may include a metal layerincluding a low-resistance metal, for example, molybdenum (Mo), titanium(Ti), copper (Cu), aluminum (Al), or an alloy thereof. In someembodiments, the auxiliary electrode 130 may further include a TCO layersuch as ITO, on or under the above-described metal layer.

FIGS. 4A through 4D are cross-sectional views and a plan viewillustrating a part (e.g., a step) of a manufacturing process of adisplay apparatus according to an embodiment of the present disclosure,illustrating operations performed, for example, to the embodiment ofFIG. 3. FIGS. 4A through 4D illustrate a process of forming a firstorganic light-emitting diode OLED1 (see FIG. 7) corresponding to thefirst pixel electrode 211.

Referring to FIG. 4A, a first dam portion 141 is formed on the secondinsulating layer 120. The first dam portion 141 is formed directly onthe auxiliary electrode 130 to surround an outer portion of a firstopening OP11. FIG. 4B is a plan view which includes a portioncorresponding to the first pixel electrode 211 of FIG. 4A. Referring toFIG. 4B, the first dam portion 141 may have a closed loop shapesurrounding the first opening OP11. As described in detail below, theshape of the first dam portion 141 as described above may be configuredto prevent a first lift-off layer 310 (FIG. 4C), which is to be formedaround the outside of (e.g., at an outer portion of) the first damportion 141, from reflowing and flowing toward and/or down into thefirst opening OP11.

The first dam portion 141 may be formed of, for example, aphotosensitive resin; that is, a photoresist. According to anembodiment, a photosensitive resin layer (not shown) may be formed inthe display area DA of the substrate 100, on which the second insulatinglayer 120 and the auxiliary electrode 130 are formed, and then thephotosensitive layer may be exposed (e.g., partially exposed) and etchedto thereby form the first dam portion 141 in an outer portion of thefirst opening OP11.

Next, referring to FIG. 4C, a first lift-off layer 310 and a first masklayer 320 are formed on the structure of FIG. 4A. An openingcorresponding to the first pixel electrode 211 to expose the first pixelelectrode 211 (e.g., a center portion of the first pixel electrode 211)is formed in each of the first lift-off layer 310 and the first masklayer 320, and the opening of the first lift-off layer 310 may be largerthan the opening of the first mask layer 320. In addition, the areasurrounded by the first dam portion 141 (i.e., the opening of the firstdam portion 141) may also be larger than the opening of the first masklayer 320. That is, the first mask layer 320 may have an undercut shapein which the first mask layer 320 protrudes into the first opening OP11more than the first dam portion 141 and the first lift-off layer 310(e.g., protrudes beyond the first dam portion 141 toward the firstopening OP11).

According to an embodiment, a non-photosensitive material layer (notshown) may be formed on the substrate 100 on which the auxiliaryelectrode 130 and the first dam portion 141 are formed, and then thenon-photosensitive material layer may be selectively removed to patternthe first lift-off layer 310, and then a photosensitive resin layer (notshown) may be formed on the non-photosensitive material layer, and thenthe photosensitive resin layer may be exposed (e.g., partially exposed)and etched to form the first mask layer 320 having an opening.

The first lift-off layer 310 formed as described above is formed aroundthe outside of (e.g., in an outer portion of) the first dam portion 141and may be spaced apart from the first dam portion 141 by a distance d(e.g., a pre-set distance d), as illustrated in FIG. 4C. The spacebetween the first dam portion 141 and the first lift-off layer 310having the distance d may be due to, or may be implemented to accountfor, the difficulty in accurately aligning the first lift-off layer 310with the first dam portion 141 in an operation of selectively removingthe non-photosensitive material of the first lift-off layer 310.

According to another embodiment, a non-photosensitive material layer(not shown) and a photosensitive resin layer (not shown) may be formedon the substrate 100 on which the auxiliary electrode 130 and the firstdam portion 141 are formed, and the photosensitive resin layer may beexposed (e.g., partially exposed) and etched to form the first masklayer 320 having an opening. Next, the non-photosensitive material layermay be selectively removed by using the first mask layer 320 to form thefirst lift-off layer 310 having an opening.

The first lift-off layer 310 formed as described above may be formed tobe in contact with the first dam portion 141. As an opening is formed byexposing (e.g., partially exposing) and etching the photosensitive resinlayer, and then the non-photosensitive material layer within the firstdam portion 141 is selectively removed through the opening, the firstdam portion 141 functions as a barrier, and a side surface of the firstlift-off layer 310 may accordingly be in direct contact with a sidesurface of the first dam portion 141, that is, an outer side surfacethereof.

The non-photosensitive material layer may be formed of a fluoroussolvent base resin. For example, the non-photosensitive material layermay include 75-95 wt % of fluoro ether in which a portion of hydrogen issubstituted with fluorine in an ether structure and 5-25 wt % of resinpolymer, but the present disclosure is not limited thereto. When thenon-photosensitive material layer includes the above-described material,the non-photosensitive material layer may be partially removed by usinga stripper in a solution form including hydrofluoroether, therebyforming the first lift-off layer 310.

An opening exposing the first pixel electrode 211, that is, a first openportion OP12, is formed in the first mask layer 320. A firstintermediate layer 221 and a first opposite electrode 231 are formed onthe first pixel electrode 211 through the first open portion OP12.Materials of the first intermediate layer 221 and/or the first oppositeelectrode 231 may be formed not only on the first pixel electrode 211but also on the first mask layer 320.

The first intermediate layer 221 may include an organic emissive layerand may further include a functional layer on and/or under the organicemissive layer. The functional layer may further include at least one ofa hole injection layer, a hole transport layer, an electron transportlayer, and an electron injection layer. The organic emissive layer mayemit red, green or blue light.

The first opposite electrode 231 may be formed of a conductive materialhaving a low work function. For example, the first opposite electrode231 may include silver (Ag), magnesium (Mg), aluminum (Al), platinum(Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium(Ir), chromium (Cr), lithium (Li), calcium (Ca), or an alloy thereof.According to an embodiment, the first opposite electrode 231 may includealuminum (Al), silver (Ag), and an alloy of Mg and Ag (Mg:Ag). In someembodiments, the first opposite electrode 231 may include an alloycontaining more silver (Ag) than magnesium (Mg).

The first intermediate layer 221 and the first opposite electrode 231may be formed using a thermal deposition method.

The first opposite electrode 231 patterned according to the first pixelelectrode 211 may be electrically connected to an opposite electrode(for example, a second opposite electrode 232, see FIG. 5C)corresponding to an adjacent pixel electrode (for example, the secondpixel electrode 212) through the auxiliary electrode 130. Each end ofthe first opposite electrode 231 may extend further than an end of thefirst intermediate layer 221 and be in direct contact with the auxiliaryelectrode 130. That is, a material of the first opposite electrode 231may be deposited in a direction perpendicular to the substrate 100 or inan oblique direction with respect to the substrate 100, and thus, thefirst opposite electrode 231 may be formed to completely cover the firstintermediate layer 221 in the opening of the first lift-off layer 310and contact the auxiliary electrode 130.

Referring to FIGS. 4A and 4C together, a height h1 of the first damportion 141 may be equal to a height h2 of the first lift-off layer 310.For example, a height h1′ from an upper surface of the substrate 100 toan upper surface of the first dam portion 141 and a height h2′ from theupper surface of the substrate 100 to an upper surface of the firstlift-off layer 310 may be equal to each other. The first dam portion 141may support the first mask layer 320 from below together with the firstlift-off layer 310.

Next, referring to FIG. 4D, a first insulating protective layer 241 isformed on the first opposite electrode 231 through the first openportion OP12. Materials of the first insulating protective layer 241 maybe formed not only on the first pixel electrode 211 but also on thefirst mask layer 320.

The first insulating protective layer 241 is formed on the firstopposite electrode 231. The first insulating protective layer 241completely covers the first opposite electrode 231 and may have a largerarea than the first opposite electrode 231. An edge of the firstinsulating protective layer 241 may cover an edge (e.g., all edges) ofthe first opposite electrode 231 and be in direct contact with theauxiliary electrode 130. The first insulating protective layer 241 mayinclude an inorganic insulating material such as a silicon nitride, asilicon oxide, or the like. An insulating protective layer such as thefirst insulating protective layer may protect layer(s) under theinsulating protective layer, for example, an opposite electrode, anintermediate layer, or the like, during a process or after the process.The first insulating protective layer 241 may be formed using, forexample, a chemical vapor deposition (CVD) method.

A high-temperature process may be performed when forming the first masklayer 320 and/or when forming the first intermediate layer 221, thefirst opposite electrode 231, and the first insulating protective layer241 by using the first mask layer 320. For example, in a bakingoperation of the first mask layer 320 after exposing and etching thefirst mask layer 320, a high-temperature operation at about 70° C. orhigher may be performed, and a deposition operation may be performed atabout 80° C. or higher during an operation of forming the first oppositeelectrode 231 and the first insulating protective layer 241 afterdepositing the first intermediate layer 221.

In a structure without a first dam portion as a comparative example, afirst lift-off layer located under a first mask layer is vulnerable to ahigh temperature due to characteristics of a material thereof, and thusmay reflow in an undercut portion of the first mask layer, flowing downwith the first mask layer. The material of the first lift-off layer ofthe structure without the dam portion may, therefore, migrate into anopening in the mask layer and may therefore interfere with formationand/or deposition of parts corresponding to the first oppositeelectrode, the first insulating protective layer, and the firstintermediate layer.

However, according to the manufacturing method of the display apparatusof the present embodiment, the first dam portion 141 is formed tofunction as a barrier between the first opening OP11 and the firstlift-off layer 310 to thereby effectively prevent or minimize reflowingof the first lift-off layer 310 during processes such as ahigh-temperature process.

After forming the first insulating protective layer 241, the first masklayer 320, the first lift-off layer 310, and the first dam portion 141are removed. Here, the first mask layer 320, the first lift-off layer310, and the first dam portion 141 may be simultaneously removed usingan identical, first solution. As the first mask layer 320 and the firstdam portion 141 may be formed using a same material, they may besimultaneously removed using an identical etching solution.‘Simultaneous’ removal means that they are removed in a singleoperation. That is, the first mask layer 320, the first lift-off layer310, and the first dam portion 141 are removed using an identicaletching solution, and the first mask layer 320 and the first dam portion141 formed using a same material may be etched first, and then the firstlift-off layer 310 may be removed. The process described above alsoapplies to embodiments of FIGS. 5D and 6D described below.

FIGS. 5A through 5D and FIGS. 6A through 6D are cross-sectional viewsand plan views of a part (e.g., a step) of a manufacturing process of adisplay apparatus according to embodiments of the present disclosure.While the process of FIGS. 4A through 4D described above correspond tothe first pixel electrode 211, FIGS. 5A through 5D and FIGS. 6A through6D may correspond to the second pixel electrode 212 and the third pixelelectrode 213, respectively. In other words, the embodiment of FIGS. 4Athrough 4D may be understood as an operation of forming the firstintermediate layer 221, the first opposite electrode 231, and the firstinsulating protective layer 241 on the first pixel electrode 211; theembodiment of FIGS. 5A through 5D may be understood as a process offorming a second intermediate layer 222, the second opposite electrode232 and a second insulating protective layer 242 on the second pixelelectrode 212; and the embodiment of FIGS. 6A through 6D may beunderstood as a process of forming a third intermediate layer 223, thethird opposite electrode 233, and a third insulating protective layer243 on the third pixel electrode 213. The process of FIGS. 4A through 4Dcorresponding to the first pixel electrode 211 may be repeated in thesame manner with respect to the second pixel electrode 212 and the thirdpixel electrode 213 as illustrated in FIGS. 5A through 5D and FIGS. 6Athrough 6D. Thus, the process will now be described briefly and thedescription provided above with reference to FIGS. 4A through 4D will bereferred regarding repeated description.

Referring to FIGS. 5A through 5D, first, a second dam portion 142 isformed on the second insulating layer 120. The second dam portion 142 isformed directly on the auxiliary electrode 130 around (e.g., tosurround) an outer portion of a second opening OP21. The second damportion 142 may have a closed loop shape surrounding the second openingOP21, as illustrated in FIG. 5B. The shape of the second dam portion 142may be configured to prevent the second lift-off layer 410 (see FIG.5C), which is to be formed around the outside of (e.g., at an outerportion of) the second dam portion 142, from reflowing and flowingtoward and/or down into the second opening OP21.

The second dam portion 142 may be formed of, for example, aphotosensitive resin; that is, a photoresist, and may include a same orsimilar material as a second mask layer 420 (see FIG. 5C) which will bedescribed later. The method of forming the second dam portion 142 may besimilar or identical to that of forming the first dam portion 141described above.

Next, the second lift-off layer 410 and the second mask layer 420 areformed on the structure of FIG. 5A. The method of forming the secondlift-off layer 410 and the second mask layer 420 may be similar oridentical to that of forming the first lift-off layer 310 and the firstmask layer 320 described above.

While FIG. 5C illustrates a structure in which the second dam portion142 is spaced apart from the second lift-off layer 410 by a distanced(e.g., a pre-set distance d) like in FIG. 4C, in some embodiments thesecond dam portion 142 may also contact the second lift-off layer 410like the first dam portion 141 contacting the first lift-off layer 310as illustrated in FIG. 8.

An opening exposing the second pixel electrode 212, that is, a secondopen portion OP22, is formed in the second mask layer 420. A secondintermediate layer 222, a second opposite electrode 232, and a secondinsulating protective layer 242 may be sequentially formed on the secondpixel electrode 212 through the second open portion OP22. Materials ofthe second intermediate layer 222, the second opposite electrode 232,and/or the second insulating protective layer 242 may be formed not onlyon the second pixel electrode 212 but also on the second mask layer 420.The second intermediate layer 222, the second opposite electrode 232,and the second insulating protective layer 242 may be patterned inapproximately the same shape via the second open portion OP22.

An operation of forming the second mask layer 420 and/or forming thesecond intermediate layer 222, the second opposite electrode 232, andthe second insulating protective layer 242 by using the second masklayer 420 may be performed at a high temperature. According to themanufacturing method of the display apparatus of the present embodiment,the second dam portion 142 is formed to function as a barrier betweenthe second opening OP21 and the second lift-off layer 410 to therebyeffectively prevent or minimize reflowing of the second lift-off layer410 in a high-temperature process.

After forming the second insulating protective layer 242, the secondmask layer 420, the second lift-off layer 410, and the second damportion 142 are removed. Here, the second mask layer 420, the secondlift-off layer 410, and the second dam portion 142 may be simultaneouslyremoved using a similar or identical first solution. As the second masklayer 420 and the second dam portion 142 are formed using a same orsimilar material, they may be simultaneously removed using a similar oridentical etching solution.

Referring to FIGS. 6A through 6D, a third dam portion 143 is formeddirectly on the auxiliary electrode 130 formed on the second insulatinglayer 120 in a same or similar manner as described above. The third damportion 143 may have a closed loop shape surrounding an outer portion ofa third opening OP31 as illustrated in the plan view of FIG. 6B. Thethird dam portion 143 may prevent a third lift-off layer 510 (see FIG.6C) from reflowing and flowing toward and/or down into the third openingOP31.

The third dam portion 143 may be formed of, for example, aphotosensitive resin—that is, a photoresist—and may include a same orsimilar material as a third mask layer 520 (see FIG. 6C) which will bedescribed later. A method of forming the third dam portion 143 may besimilar or identical to that of forming the first dam portion 141 andthe second dam portion 142 described above.

Next, the third lift-off layer 510 and the third mask layer 520 areformed on the structure of FIG. 6A. The method of forming the thirdlift-off layer 510 and the third mask layer 520 may be similar oridentical to that of forming the first lift-off layer 310 and the firstmask layer 320 described above.

While FIG. 6C illustrates the structure in which the third dam portion143 is spaced apart from the third lift-off layer 510 by a distance d(e.g., a pre-set distance d) like in FIG. 4C, in some embodiments thethird dam portion 143 may also contact the third lift-off layer 510 likethe first dam portion 141 contacting the first lift-off layer 310 asillustrated in FIG. 8.

An opening exposing the third pixel electrode 213, that is, a third openportion OP32, is formed in the third mask layer 520. A thirdintermediate layer 223, a third opposite electrode 233, and a thirdinsulating protective layer 243 may be sequentially formed on the thirdpixel electrode 213 through the third open portion OP32. Materials ofthe third intermediate layer 223, the third opposite electrode 233,and/or the third insulating protective layer 243 may be formed not onlyon the third pixel electrode 213 but also on the third mask layer 520.The third intermediate layer 223, the third opposite electrode 233, andthe third insulating protective layer 243 may be patterned inapproximately the same shape via the third open portion OP32.

An operation of forming the third mask layer 520 and/or forming thethird intermediate layer 223, the third opposite electrode 233, and thethird insulating protective layer 243 by using the third mask layer 520may be performed at a high temperature. According to the manufacturingmethod of the display apparatus of the present embodiment, the third damportion 143 is formed to function as a barrier between the third openingOP31 and the third lift-off layer 510 to thereby effectively prevent orminimize reflowing of the third lift-off layer 510 in a high-temperatureprocess.

After forming the third insulating protective layer 243, the third masklayer 520, the third lift-off layer 510, and the third dam portion 143are removed. Here, the third mask layer 520, the third lift-off layer510, and the third dam portion 143 may be simultaneously removed using asimilar or identical first solution. As the third mask layer 520 and thethird dam portion 143 are formed using a same or similar material, theymay be simultaneously removed using a similar or identical etchingsolution.

FIG. 7 is a cross-sectional view of a display apparatus according toembodiments of the present disclosure. After removing the third masklayer 520, the third lift-off layer 510, and the third dam portion 143from the embodiment of the display apparatus shown in FIG. 6D, thedisplay apparatus according to the present embodiment may have astructure as illustrated in FIG. 7.

FIG. 9 is a cross-sectional view illustrating a part (e.g., a step) of amanufacturing process of a display apparatus according to anotherembodiment of the present disclosure, and FIG. 10 is a schematicenlarged view of a region B of FIG. 9. FIG. 10 illustrates an operationin which the region B of FIG. 9 is deformed during a high-temperatureprocess.

FIG. 9 corresponds to an alternative embodiment of the operationillustrated in FIG. 4C, in which a height h1″ of the first dam portion141 may be lower than (e.g., less than) the height h2 of the firstlift-off layer 310. The height h1″ of the first dam portion 141 may beunderstood as a height from an upper surface of the auxiliary electrode130 to the upper surface of the first dam portion 141, and the height h2of the first lift-off layer 310 may be understood as a height from theupper surface of the auxiliary electrode 130 to the upper surface of thefirst lift-off layer 310.

The first dam portion 141 functions as a barrier to prevent the firstlift-off layer 310 from reflowing toward or into the first opening OP11in a high-temperature process. The height h1″ of the first dam portion141 is sufficient to prevent reflowing of the first lift-off layer 310,and the height h1″ of the first dam portion 141 does not necessarilyhave to be equal to the height h2 of the first lift-off layer 310.

Referring to FIG. 10, a portion of the first lift-off layer 310 mayreflow during the high-temperature process. However, the first damportion 141 having the height h1″ may block the portion of the firstlift-off layer 310 that reflows from passing the first dam portion 141.The first lift-off layer 310 having a portion that has reflowed to thefirst dam portion 141 may contact an outer external surface 141OE of thefirst dam portion 141. The height h1″ of the first dam portion 141 maybe varied according to design considerations of particular embodiments,and in some embodiments may be equal to or greater than ½ of the heighth2 of the first lift-off layer 310.

In some embodiments, the first dam portion 141 and the first lift-offlayer 310 may contact each other as illustrated in FIG. 8 as describedabove. In other embodiments, as depicted in FIG. 9, the first damportion 141 and the first lift-off layer 310 may be spaced apart fromeach other by a distance d. As the height h1″ of the first dam portion141 is lower than the height h2 of the first lift-off layer 310, thespace formed by the spacing apart of the first lift-off layer 310 andthe first dam portion 141 may provide a space where portions of thefirst lift-off layer 310 that reflow may fill without passing the firstdam portion 141.

Although the description with reference to FIGS. 9 and 10 was withrespect to the first dam portion 141, the same may apply to the seconddam portion 142 and the third dam portion 143.

While the manufacturing method of the display apparatus has beendescribed above, the present disclosure is not limited thereto. Forexample, a display apparatus manufactured according to the manufacturingmethod of a display apparatus described above also falls within thescope of the present disclosure.

FIG. 7 is a schematic cross-sectional view of a display apparatusaccording to an embodiment of the present disclosure.

After removing the third mask layer 520, the third lift-off layer 510,and the third dam portion 143, the display apparatus according to thepresent embodiment may have a structure as illustrated in FIG. 7.

The first through third pixels PX1, PX2, and PX3 may include a firstorganic light-emitting diode OLED1, a second organic light-emittingdiode OLED2, and a third organic light-emitting diode OLED3,respectively, that are connected to the pixel circuits PC. The firstthrough third organic light-emitting diodes OLED1, OLED2, and OLED3 mayeach include a pixel electrode, an intermediate layer, and an oppositeelectrode. The first organic light-emitting diode OLED1 includes thefirst pixel electrode 211, the first intermediate layer 221, and thefirst opposite electrode 231. The second organic light-emitting diodeOLED2 includes the second pixel electrode 212, the second intermediatelayer 222, and the second opposite electrode 232. The third organiclight-emitting diode OLED3 includes the third pixel electrode 213, thethird intermediate layer 223, and the third opposite electrode 233.

The first intermediate layer 221 and the first opposite electrode 231are patterned to correspond to the first pixel electrode 211, and thesecond intermediate layer 222 and the second opposite electrode 232 arepatterned to correspond to the second pixel electrode 212, and the thirdintermediate layer 223 and the third opposite electrode 233 arepatterned to correspond to the third pixel electrode 213.

Although the first through third opposite electrodes 231, 232, and 233patterned in accordance with the first through third pixel electrodes211, 212, and 213, respectively, are spaced apart from each other, thefirst through third opposite electrodes 231, 232, and 233 may beelectrically connected to each other via the auxiliary electrode 130.Ends of the first through third intermediate layers 221, 222, and 223may extend further than the ends of the first through third intermediatelayers 221, 222, and 223 to directly contact the auxiliary electrode130.

The first through third insulating protective layers 251, 252, and 253are located on the first through third opposite electrodes 231, 232, and233, respectively. The first through third insulating protective layers251, 252, and 253 are spaced apart from each other, and may berespectively patterned on the first through third opposite electrodes231, 232, and 233. The first through third insulating protective layers251, 252, and 253 may completely cover the first through third oppositeelectrodes 231, 232, and 233, respectively. Widths of the first throughthird insulating protective layers 251, 252, and 253 may be greater thanwidths of the first through third opposite electrodes 231, 232, and 233.

According to embodiments of the present disclosure, a manufacturingmethod of a display apparatus may be implemented in which a defect ratein a manufacturing process is reduced and product reliability isincreased. Further, according to embodiments of the present disclosure,a display apparatus amenable to being manufactured using a method inwhich a defect rate is reduced and product reliability is increased maybe implemented. The scope of the present disclosure is not limited bythe above-described effects.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While embodiments of the present disclosure have been described withreference to the figures, it will be understood by those of ordinaryskill in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the presentdisclosure, and that such embodiments should therefore not be understoodto narrow the scope of the invention as defined by the following claimsand equivalents thereof.

What is claimed is:
 1. A method of manufacturing a display apparatus,the method comprising: forming a first pixel electrode for emission of afirst color on a substrate; forming an insulating layer, the insulatinglayer covering edges of the first pixel electrode and having a firstopening exposing a center portion of the first pixel electrode; (a-1)forming a first dam portion on the insulating layer around the firstopening; (b-1) forming a first lift-off layer on the insulating layeraround the outside of the first dam portion and comprises an openingexposing the first pixel electrode; (c-1) forming a first mask layer onthe first lift-off layer, the first mask layer having a first openportion corresponding to the first opening; (d-1) forming a firstintermediate layer on the first pixel electrode through the first openportion; (e-1) forming a first opposite electrode on the firstintermediate layer through the first open portion; (f-1) forming a firstinsulating protective layer on the first opposite electrode through thefirst open portion; and (g-1) removing the first mask layer, the firstlift-off layer, and the first dam portion.
 2. The method of claim 1,wherein the first dam portion and the first mask layer comprise a samematerial.
 3. The method of claim 1, wherein the removing of the firstmask layer, the first lift-off layer, and the first dam portioncomprises simultaneously removing the first mask layer, the firstlift-off layer, and the first dam portion using a first solution.
 4. Themethod of claim 1, wherein a height of the first dam portion is equal toa height of the first lift-off layer.
 5. The method of claim 1, whereinan edge of the first mask layer around the first open portion has anundercut shape protruding beyond the first dam portion toward the firstopening.
 6. The method of claim 5, wherein an upper surface of the firstdam portion contacts a lower surface of the first mask layer such thatthe first dam portion supports the first mask layer from below.
 7. Themethod of claim 1, wherein the first dam portion and the first lift-offlayer are spaced apart from each other.
 8. The method of claim 1,further comprising, before forming the first dam portion, patterning anauxiliary electrode on the insulating layer.
 9. The method of claim 8,wherein the first opposite electrode directly contacts the auxiliaryelectrode to electrically connect to the auxiliary electrode.
 10. Themethod of claim 1, wherein the first insulating protective layercomprises an inorganic insulating material.
 11. The method of claim 10,wherein an end of the first insulating protective layer is spaced apartfrom the first dam portion.
 12. The method of claim 1, wherein a heightof the first dam portion is less than a height of the first lift-offlayer.
 13. The method of claim 1, wherein the first dam portion and thefirst mask layer contact each other.
 14. The method of claim 1, whereinthe first lift-off layer comprises a fluorous solvent base resin. 15.The method of claim 1, wherein the first dam portion has a closed loopshape surrounding the first opening.
 16. The method of claim 1, afterremoving the first mask layer, the first lift-off layer, and the firstdam portion: further comprising, forming a second pixel electrode foremission of a second color; forming the insulating layer covering edgesof the second pixel electrode and having a second opening exposing acenter portion of the second pixel electrode; (a-2) forming a second damportion on the insulating layer around the second opening; (b-2) forminga second lift-off layer on the insulating layer around the outside ofthe second dam portion and comprises an opening exposing the secondpixel electrode; (c-2) forming a second mask layer on the secondlift-off layer, the second mask layer having a second open portioncorresponding to the second opening; (d-2) forming a second intermediatelayer on the second pixel electrode through the second open portion;(e-2) forming a second opposite electrode on the second intermediatelayer through the second open portion; (f-2) forming a second insulatingprotective layer on the second opposite electrode through the secondopen portion; and (g-2) simultaneously removing the second mask layer,the second lift-off layer, and the second dam portion by using anidentical etching solution.
 17. The method of claim 16, after removingthe second mask layer, the second lift-off layer, and the second damportion: further comprising, forming a third pixel electrode foremission of a third color on a substrate; forming the insulating layercovering edges of the third pixel electrode and having a third openingexposing a center portion of the third pixel electrode; (a-3) forming athird dam portion on the insulating layer around the third opening;(b-3) forming a third lift-off layer on the insulating layer around theoutside of the third dam portion and comprises an opening exposing thethird pixel electrode; (c-3) forming a third mask layer on the thirdlift-off layer, the third mask layer having a third open portioncorresponding to the third opening; (d-3) forming a third intermediatelayer on the third pixel electrode through the third open portion; (e-3)forming a third opposite electrode on the third intermediate layerthrough the third open portion; (f-3) forming a third insulatingprotective layer on the third opposite electrode through the third openportion; and (g-3) simultaneously removing the third mask layer, thethird lift-off layer, and the third dam portion by using an identicaletching solution.
 18. The method of claim 17, in step (b-1), the firstlift-off layer covers an upper portion of the second pixel electrode andan upper portion of the third pixel electrode.
 19. The method of claim17, in step (b-2), the second lift-off layer covers an upper portion ofthe first pixel electrode and an upper portion of the third pixelelectrode.
 20. The method of claim 17, in step (b-3), the third lift-offlayer covers an upper portion of the first pixel electrode and an upperportion of the second pixel electrode.